Videodrome:
Do you have cable tv? If so, have any changes occured there?
Yes I do have cable and I have a new carrier that I am unhappy with since they have not corrected the billing. However when I enable the RCN mode for the cable I do not get any hum thru my 804's.

Also, are any of your speaker cables intertwined with power cables?
I seperated all of the power cables (ROMAX) from any Home Theater lines.

And/or did you run any in-wall wiring in close proximity to speaker cables?
NO.

I have a tester to check the ground in the outlets.

The hum is coming directly from the line conditioners. No where else. When I engage the laser disc mode I get a hum in all of my speakers. I use to have the same issue when I turned the cable box on but I since eliminated the hum because of a new component cable I installed.
The upside of it is I feel I am making progress but I am somewhat impatient.

Frank